PURPOSE: To immediately obtain a perspective line for easy drawing of a perspective view, by connecting the ends of a micrometer for adjusting a course of traverse and a wire drawing ruler for drawing a perspective line through a parallel link mechanism, pivotally supporting said micrometer at the center thereof by a pivotal shaft at a measuring point in an oscillating manner, and connecting said parallel link mechanism from said pivotally supported portion.

CONSTITUTION: An adjusting mechanism C of a source of traverse provided in a vertical rail 1 of a drawing instrument A and a line drawing ruler 2 consisting of a protractor-type L-shaped ruler provided in a sliding body 1' of the vertical rail 1 are connected through a parallel link mechanism D. A base plate 3 and an attaching plate 4 of an elevational view are separated a distance on the vertical rail 1, in an overlapping manner. On the upper attaching plate 4, a horizontal line 5 at the height of one's eyes and an extending line 6 from a measuring point which is orthogonal to the horizontal line 5 are linearly indicated. A pivotal shaft 8 is inserted at a position of the measuring point 7 which is a point where the lines 5 and 6 cross at a right angle. A cross-shaped transparent ruler 9 for obtaining a course of traverse is fixed at the center thereof to the front surface of the pivotal shaft 8, while one end of an arm piece 10 is fixed to the reverse side of the pivotal shaft 8. A horizontal line 5' and an extending line 6' from the measuring point are indicated by the ruler 9. The free end of the arm piece 10 extends in the same direction as the horizontal line 5' and an elongated hole track 11 runs in the same direction as the horizontal line 5'.